Ka 4 Rhönlerche II outlanding in gravel pit near Winterthur airfield

On July 5, 1964, a Ka 4 Rhönlerche II experienced an outlanding near Winterthur airfield in Switzerland. The flight was part of a training exercise conducted by the Segelfluggruppe Winterthur. During the landing approach, the student pilot misjudged the altitude and encountered downdrafts, leading to an outlanding in a nearby gravel pit. The aircraft sustained damage to its fuselage and wing connections, but the pilot was uninjured. The incident occurred during the group's first use of the newly opened airfield.

1. Winch launch circuit: The student pilot launched by winch from Winterthur-Hegmatten and flew a standard training circuit, reaching about 260 m above the field before positioning for landing.
2. Low experience level: The student had limited overall gliding experience and this was only his second flight from the newly opened Winterthur-Hegmatten airfield, reducing his familiarity with its circuit and height cues.
3. Low circuit altitude: Before starting the approach he descended in turns to roughly 100 m above the field, which was at the lower limit for executing a normal landing pattern.
4. Altitude misjudged: Believing he still had sufficient height, the student turned onto a normal-length final approach similar to the preceding dual check flight, despite being lower than appropriate.
5. Downdraft on final: While on final over the water surface of the gravel pit in line with runway 05, the glider encountered sinking air that further reduced its glide path.
6. Committed to outlanding: Recognizing he could no longer reach the airfield, the pilot continued just above the water surface, which lay about 4 m below field level, and elected to land in the gravel pit area.
7. Outlanding - damage: The glider touched down on a gravel bank and then collided head-on with the edge of the pit, damaging the fuselage nose and wing attachments while the pilot remained uninjured.